Scientific Forecaster Discussion

Synopsis...cool conditions with scattered rain and mountain snow showers will persist today as a trough pushes through the region. Drier conditions and slightly warmer weather is expected Thursday before a marked warming trend commences Friday. Over the weekend high temperatures will rise above normal thanks to high pressure building across the West Coast...and staying put through early next week.

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Update...increasing clouds and chances for precipitation today as a system moves in from the north. Morning models continue to highlight Lincoln and northern Mohave counties as the most favorable areas for shower activity producing light rain/snow accumulations. Will be on the lookout for developing thunderstorms which will be capable of producing brief moderate rain, gusty winds and small hail. Forecast in good shape and no updates currently needed. -Salmen-

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Aviation...for McCarran...mostly clear conditions through 19z when the atmosphere begins to destabilize and isolated vicinity showers break out. Ceilings in the 5-6kft range will be possible with any activity in the immediate vicinity of the airfield but broken ceilings in the 7-8kft range will be predominant. West to southwest winds of 9 to 12 kts favored in the afternoon but direction and speed may be variable at times due to shower activity in the area. Improving conditions expected after 00z with a push of northerly winds expected after 3z.

For the rest of southern Nevada...northwest Arizona...and southeast California...scattered showers possible today especially east of a line from kdag-kdra-kely. Isolated thunderstorms are possible with strong updrafts and gusty surface winds. Ceilings near shower activity will range from 4-6kft. A push of northerly winds expected Tuesday night into Wednesday with winds of 15-25kts possible down the Colorado River valley.

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Previous discussion...145 am PST...

Short term...today through Wednesday night.

Shower activity has diminished this morning across most of the forecast area with the exception of some light returns showing up on radar across northern Mohave County. I expect that with return of daytime heating after sunrise this morning things will quickly liven up again as the trough axis remains overhead and an additional shortwave pushes through the Great Basin. With the trough axis passing directly overhead and 500mb temperatures in the -25c to -28c range...there will once again be marginal instability present to support a few lightning strikes and perhaps a stronger updraft or two may produce some small hail.

The shortwave driving this activity along with the entire trough axis which stretches all the way down into the Baja California will begin to shift eastward by late afternoon. Drier and more stable air will invade from northwest to southeast with shower and thunderstorm chances becoming limited to Mohave County by late in the evening where a few lingering showers will be possible through the early overnight period. As the trough exits...a push of northerly winds will follow as high pressure builds in behind the storm system. These northerly winds will be strongest down the Colorado River late Wednesday night through early Thursday morning before slowly subsiding by early Thursday morning.

Long term...Thursday through Monday.

The medium range models continue to show an amplified ridge along the West Coast Thursday that will slowly migrate inland over the weekend and early next week providing dry and mild weather for our forecast area. A weak upper low is forecast to develop near the base of the ridge over northern Baja California Thursday through Friday/Saturday which will lead to periods of north breezes...especially down the Colorado River valley near Laughlin and Bullhead City. Temperatures will begin a noticeable warming trend with highs climbing back into the 70s across the Mojave Desert region for the weekend.

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Spotter information statement...spotters are requested to report any significant weather according to Standard operating procedures. &&